The present invention concerns a valve with a valve housing which consists of two housing halves, each of which has a flange section which is screwed or bolted together with the other flange section and a connection piece that is welded to each flange section, and in the separation plane which runs transversely to the valve opening, one half each of the shaft guide for the valve shaft is located with a valve flap which can swivel around a shaft and with a sealing ring which seals off the valve shaft and forms the valve seat and is contained in an undercut recess of the valve housing which runs around and surrounds the valve opening.
These valves are used particularly in the food industry. They consist of two flanges which have screw connection pieces on their external surfaces which mate and are bolted together with their inside surfaces. The two flanges are normally produced as heavy turned elements, which leads to high material costs, given the use of high quality steels, which are usually necessary. The production of the semicylindrical shaft guides that run transversely to the direction of the flow not only makes necessary an additional difficult metal cutting operation, but also necessitates that the flanges have quite a heavy thickness.
In order to reduce the material consumption of high quality steel, it has already been suggested that the two housing halves, each consisting of a flange section and a connection piece section, be welded together, but otherwise they are produced from heavy turned pieces in the traditional way. To be sure, a considerable quantity of material and roughing work on the lathe is saved by doing this, but otherwise the extent of the metal cutting work is hardly reduced. In addition, there is still an inside processing of the weld seam, which extends almost into the valve opening.
The object of the invention is to create a valve of this type which can be produced with a considerably lower consumption of material and less metal cutting work.
This object has been solved in accordance with the invention in that the flange sections each consist of a stamped sheet element which has an angular area that forms the flanges in which the shaft guide recesses are formed and a connection piece area surrounding the valve opening that is welded to the connection pieces.
The advantages of the valve in accordance with the invention are the uncomplicated production with a low use of metal cutting processing. The entire flange section can be punched out of and stamped from a sheet practically without any subsequent metal cutting work. The saving of material is considerable. For example, the flange section of a valve with a rated width of 50 mm, which previously consisted of approximately 15 mm of heavy massive material, is now produced from sheet metal approximately 2.5 mm thick without the stability of the valve suffering from this. In all, it is possible to reduce the weight of a valve to a quarter of the previous weight, the saving in material being possible even greater, since there is hardly any waste in the course of production in the case of the valve in accordance with the invention.
Preferably half of the surrounding recess which carries the seal can be formed between the annular area and the connection piece area of the flange section. It can be recognized that the simple and material-saving production is aided by this measure. On account of this recess, the flange had to be relatively thick in the case of the previous valves in order to be able to cut in the recess sufficiently deeply. The design as an annular stamping adjacent to the annular area not only provides for an additional reinforcement of the flange section, but also for a good connection of the shaft guide recesses to this recess. It is advantageous for the stamping that forms the recess to be designed undercut. This undercutting is necessary in order to hold the sealing ring, on which considerable forces act during the operation of the valve. While this undercutting previously had to be produced by cutting in while working on the lathe, it can now be formed in the course of the stamping without additional effort.
In the case of an advantageous form of embodiment of the invention, the connection piece area of the flange section can be placed over an element of the connection piece and welded on the outside periphery. When this is done, it is preferable that the portion of the connection piece over which the connection area of the flange section is placed be designed as a thin walled tube projection of the connection piece. The tube projection can cover the weld seam inside. By means of this manner of connection of the two elements to form a valve housing, one provides not only for a perfet centering of the two parts welded to each other, but in addition, the inside wall of the valve opening remains completely smooth as well and therefore does not need to be reworked. In addition, in this way, the difference in diameter between the thin walled sheet of the stamped elements and the usually thicker walled connection pieces can be bridged advantageously in that the wall thickness of the connection piece at the point of welding is advantageously as large as the wall thickness of the pipe projection plus the wall thickness of the sheet which forms the flange section. An additional advantageous characteristic consists in the fact that the end of the pipe projection extends in the area of the recess and forms an edge which constricts the recess toward the valve opening. Thus, this edge forms the continuation of the undercutting which has already been provided in the course of the stamping. At the transition from the boundaries of the recess to the annularly shaped connection piece area, the sheet is formed with as low a bending radius as possible without the sealing ring lying free at the front edges of its internal side facing the valve opening. In this way, not only are flow losses avoided, but also points of attack for tearing out the sealing ring. In addition, points for the collection of contaminants are avoided by means of this particularly smooth opening hole, something which should be avoided unconditionally in the case of use in the food industry as foci for bacteria.